基本概念
Android 通知（Notification）是应用向用户显示重要信息的标准化方式，即使应用未运行也能提醒用户。
基本用法
1.调用Context的getSystemService得到NotificationManager管理通知
NotificationManager manager=(NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);2.使用Builder构造器创建Notification对象（使用support库中的NotificationCompat类的构造器创建Notification对象，保证兼容性）
Notification notification=new NotificationCompat.Builder(context).build();3.在build之前连缀任意多的设置方法
Notification notification=new NotificationCompat.Builder(context).
setContentTitle("content title").
setContentText("content text")
.setWhen(System.currentTimeMillis())
.setSmallIcon(R.drawable.ic_launcher_background)
.setLargeIcon(BitmapFactory.decodeResource(getResources(),R.drawable.ic_launcher_foreground))
.build();
setContentTitle("content title")：设置通知的标题内容
setContentText("content text")：设置通知的正文内容
setWhen(System.currentTimeMillis())指定通知被创建的时间，以毫秒为单位
setSmallIcon：用于设置通知的小图标，小图标会显示在系统通知栏上
setLargeIcon：设置通知的大图标，当下拉系统通知栏时就可以看到设置的大图标
4.调用NotificationManager的notify方法可以让通知显示出来
manager.notify(1,notification);接收两个参数，id和Notification对象
在 Android 13（API 33） 或更高版本中，应用必须声明并动态申请
POST_NOTIFICATIONS权限才能向用户显示通知。
public class MainActivity extends AppCompatActivity {
private static final String CHANNEL_ID = "default_channel";
private static final int NOTIFICATION_ID = 1;
private static final int REQUEST_CODE_POST_NOTIFICATIONS = 100;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
EdgeToEdge.enable(this);
setContentView(R.layout.activity_main);
Button sendNotice=(Button)findViewById(R.id.send);
sendNotice.setOnClickListener(this::onClick);
Context context=MainActivity.this;
// createNotificationChannel();
}
public void onClick(View v){
if(R.id.send==v.getId()){
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
if (ContextCompat.checkSelfPermission(this, Manifest.permission.POST_NOTIFICATIONS)
== PackageManager.PERMISSION_GRANTED) {
sendNotification();
} else {
// 请求通知权限
ActivityCompat.requestPermissions(this,
new String[]{Manifest.permission.POST_NOTIFICATIONS},
REQUEST_CODE_POST_NOTIFICATIONS);
}
} else {
// Android 12 及以下直接发送通知
sendNotification();
}
}
}
public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if (requestCode == REQUEST_CODE_POST_NOTIFICATIONS) {
if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
sendNotification();
} else {
Toast.makeText(this, "通知权限被拒绝", Toast.LENGTH_SHORT).show();
}
}
}
private void sendNotification() {
NotificationManager manager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
Notification notification = new NotificationCompat.Builder(this, CHANNEL_ID)
.setContentTitle("Content Title")
.setContentText("Content Text")
.setWhen(System.currentTimeMillis())
.setSmallIcon(R.drawable.ic_launcher_background)
.setLargeIcon(BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher_foreground))
.setPriority(NotificationCompat.PRIORITY_DEFAULT)
.build();
manager.notify(NOTIFICATION_ID, notification);
}
}
设置通知点击效果
使用PendingIntent，可以用于启动活动、服务以及发送广播，可以简单理解为延迟执行的Intent
提供静态方法获取PendingIntent的实例
getActivity getBroadcast getService 接收的参数相同：第一个参数Context，第二个参数一般传入0，第三个参数Intent，第四个参数确定PendingIntent的行为，FLAG_ONE_SHOT、FLAG_NO_CREATE、FLAG_CANCEL_CURRENT、FLAG_UPDATE_CURRENT,通常传入0
通过NotificationCompat.Builder构造器连缀setContentIntent方法，接收参数为PendingIntent对象，设置相应的逻辑
在 Android 12（API 31）及以上版本中，创建
PendingIntent时必须显式指定FLAG_IMMUTABLE或FLAG_MUTABLE标志。
FLAG_IMMUTABLE（推荐）：创建的PendingIntent不可修改
FLAG_MUTABLE：允许修改（仅当需要动态更新时才使用）
private void sendNotification() {
NotificationManager manager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
Intent intent=new Intent(this, NotificationActivity.class);
PendingIntent pi=PendingIntent.getActivity(this,0,intent, PendingIntent.FLAG_IMMUTABLE);
Notification notification = new NotificationCompat.Builder(this, CHANNEL_ID)
.setContentTitle("Content Title")
.setContentText("Content Text")
.setWhen(System.currentTimeMillis())
.setSmallIcon(R.drawable.ic_launcher_background)
.setLargeIcon(BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher_foreground))
.setPriority(NotificationCompat.PRIORITY_DEFAULT)
.setContentIntent(pi)
.build();
manager.notify(NOTIFICATION_ID, notification);
}设置点击后取消通知图标
1.在NotificationCompat.Builder中连缀一个setAutoCancel方法，传入true表示点击了这个通知后通知会自动取消
Notification notification = new NotificationCompat.Builder(this, CHANNEL_ID)
.setContentTitle("Content Title")
.setContentText("Content Text")
.setWhen(System.currentTimeMillis())
.setSmallIcon(R.drawable.ic_launcher_background)
.setLargeIcon(BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher_foreground))
.setPriority(NotificationCompat.PRIORITY_DEFAULT)
.setContentIntent(pi)
.setAutoCancel(true)
.build();2.显示调用NotificationManager的cancel方法
在跳转后的Activity中显示调用cancel方法
public class NotificationActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
EdgeToEdge.enable(this);
setContentView(R.layout.activity_notification);
NotificationManager manager=(NotificationManager) getSystemService(NOTIFICATION_SERVICE);
manager.cancel(1);
}
}cancel中的参数代表该通知的id
通知的API
setSound：在通知发出时播放一段音频，接收Uri参数，在指定音频文件时要获取指定音频文件的URI
private void sendNotification() {
NotificationManager manager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
Intent intent=new Intent(this, NotificationActivity.class);
PendingIntent pi=PendingIntent.getActivity(this,0,intent, PendingIntent.FLAG_IMMUTABLE);
Notification notification = new NotificationCompat.Builder(this, CHANNEL_ID)
.setContentTitle("Content Title")
.setContentText("Content Text")
.setWhen(System.currentTimeMillis())
.setSmallIcon(R.drawable.ic_launcher_background)
.setLargeIcon(BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher_foreground))
.setPriority(NotificationCompat.PRIORITY_DEFAULT)
.setContentIntent(pi)
.setSound(Uri.fromFile(new File("/system/media/audio/ringtones/Luna.ogg")))
.build();
manager.notify(NOTIFICATION_ID, notification);
}setVibrate：在通知到来时让手机震动，使用vibrate属性，是一个长整型的数组，用于设置手机静止和振动的时长，以毫秒为单位，数组元素交替表示手机静止和振动的时长
Notification notification = new NotificationCompat.Builder(this, CHANNEL_ID)
.setContentTitle("Content Title")
.setContentText("Content Text")
.setWhen(System.currentTimeMillis())
.setSmallIcon(R.drawable.ic_launcher_background)
.setLargeIcon(BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher_foreground))
.setPriority(NotificationCompat.PRIORITY_DEFAULT)
.setContentIntent(pi)
.setSound(Uri.fromFile(new File("/system/media/audio/ringtones/Luna.ogg")))
.setVibrate(new long[]{0,100,100,1000})
.build();
<uses-permission android:name="android.permission.VIBRATE" />setDefaults：直接使用通知的默认效果
Notification notification = new NotificationCompat.Builder(this, CHANNEL_ID)
.setContentTitle("Content Title")
.setContentText("Content Text")
.setWhen(System.currentTimeMillis())
.setSmallIcon(R.drawable.ic_launcher_background)
.setLargeIcon(BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher_foreground))
.setPriority(NotificationCompat.PRIORITY_DEFAULT)
.setContentIntent(pi)
.setDefaults(NotificationCompat.DEFAULT_ALL)
.build();
高级功能
setStyle：构建富文本的通知信息，接收NotificationCompat.Style参数，这个参数用来构建具体的富文本信息
.setStyle(new NotificationCompat.BigPictureStyle().bigPicture(BitmapFactory.decodeResource(getResources(),R.drawable.ic_launcher_background))) 创建了NotificationCompat.BigPictureStyle()对象，用于设置大图片，然后调用bigPicture方法传入图片，通过BitmapFactory.decodeResource方法将图片解析成Bitmap对象再传入bigPicture方法.setStyle(new NotificationCompat.BigTextStyle().bigText("ggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggg")) 创建了NotificationCompat.BigTextStyle()对象，用于封装长文字信息，调用bigText方法将文字内容传入
setPriority：用于设置通知的重要程度，接受一个整型参数用于设置这条通知的重要程度，PRIORITY_DEFAULT表示默认的重要程度，PRIORITY_MIN表示最低的重要程度，只在用户下拉状态栏时显示；PRIORITY_LOW表示较低的重要程度；PRIORITY_HIGH表示较高的重要程度；PRIORITY_MAX表示最高的重要程度